This proposal describes the Johns Hopkins-University of Maryland field center for the Prospective Cohort Study of Chronic Renal Insufficiency, also termed CRIC. The incidence and prevalence of end stage kidney disease are relentlessly increasing, along with attendant co-morbidities, particularly cardiovascular disease. CRIC is a longitudinal, observational study that will determine the risk factors for progression of chronic renal insufficiency and the risk factors for cardiovascular disease in a cohort of individuals with impaired kidney function. Participants will be 3,000 individuals (250 at Hopkins, 250 at Maryland), 50% diabetic and 50% non-diabetic, with an estimated glomerular filtration rate (GFR) of 30-70 ml/min/1.73 m2. The primary recruitment strategy will be to identify individuals with an elevated creatinine that corresponds to this GFR range. Both Hopkins and U.Maryland have the proven capacity to generate lists of such individuals. These 2 medical centers are the largest health care delivery systems in the Baltimore metropolitan area, which is populated by 1.6 million persons. The locations of the two institutions should facilitate enrollment of a diverse cohort, many of whom will be indigent. Baseline data will be collected over3 visits (a brief eligibility visit and 2 subsequent visits). Outcomes will be ascertained at an annual in-person follow-up visit and by telephone surveillance. Core measurements will include questionnaires, GFRs, echocardiograms, and biological specimens. Study investigators have a proven track record of successfully designing and conducting large-scale, collaborative research studies. Specifically, they have successfully recruited large cohorts of participants, have achieved high follow-up rates, have collected virtually all of the major measurements proposed in this study, and have made substantive scientific contributions through publication and presentation of their findings. The impressive infrastructure of the two institutions and the large population of the Baltimore metropolitan area will further enhance the potential for success. In short, the Hopkins-U.Maryland field center is extremely well positioned to accomplish each of the major task required of the CRIC field centers and to contribute to the overall success of this vitally important study.